Rigi10™ Malleable Penile Prosthesis
Also Known As
Sacral nerve stimulation (SNS), Sacral nerve modulation, SNM, SNS, Sacral neuromodulator, InterStim therapy, Axonics therapy
Definition
Sacral neuromodulation (SNM) is a well-established, minimally invasive therapeutic approach that involves implanting a neurostimulator device to deliver controlled electrical impulses to the sacral nerves (typically S3-S4).1 2 This stimulation effectively modulates neural pathways between the lower urinary tract, bowel, and brain, restoring normal function in patients with various urinary and fecal disorders.3 The therapy works primarily by evoking afferent activity of the sacral nerve roots, which modulates sensory processing and the micturition reflex, rather than through direct motor stimulation.4 5 This neuromodulation can facilitate voiding by inhibiting micturition guarding reflexes, resulting in decreased urethral sphincter tone and functional detrusor contraction in cases of retention, or by blocking irregular C fiber activity in cases of overactivity.6 7
Clinical Context
Sacral neuromodulation is primarily indicated for patients with refractory lower urinary tract and bowel dysfunctions who have not responded adequately to conservative treatments or pharmacological interventions.1 3 The therapy received FDA approval for urge incontinence in 1997 and for urgency/frequency and non-obstructive urinary retention in 1999.3
Key clinical applications include:
- Urinary Disorders: Overactive bladder syndrome (with or without incontinence), urinary urgency, frequency, and non-obstructive urinary retention.1 2 3 Studies have demonstrated an 83% success rate for overactive bladder among patients who underwent implantation.1
- Bowel Disorders: Chronic fecal incontinence, with approximately 80% of patients experiencing lasting improvement of at least 50% in their leakage issues.1
- Neurogenic Conditions: Effective in neurogenic bladder conditions such as multiple sclerosis, meningomyelocele, and spinal cord injury.1
The procedure involves a two-stage approach:
- An initial trial phase where a temporary lead is placed to assess therapeutic response
- Permanent implantation of the neurostimulator if the trial demonstrates significant symptom improvement (typically >50%)2 3
Patient selection criteria include:
- Failed conservative and pharmacological treatments
- Absence of anatomical obstruction or correctable neurological disorder
- Psychological stability and ability to operate the device
- Successful response during the trial phase2
The implantation procedure is performed under local or general anesthesia with the patient in prone position. The quadripolar lead is positioned percutaneously under fluoroscopy guidance through the third sacral foramen following the trajectory of S3.3 Modern devices include rechargeable systems and MRI-safe options, with battery longevity ranging from 5 to 15 years depending on the specific system.3